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Nuclear Theory·nucl-th

Friday·August 14, 2020

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 12 Aug 2020]

    Emergent Sp(3,R) dynamical symmetry in the nuclear many-body system from an ab initio description

    A. E. McCoy · M. A. Caprio · T. Dytrych · P. J. Fasano

    Ab initio nuclear theory provides not only a microscopic framework for quantitative description of the nuclear many-body system, but also a foundation for deeper understanding of emergent collective correlations. A symplectic Sp(3,R)U(3) dynamical symmetry is identified in ab initio predictions, from a no-core configuration interaction approach, and found to provide a qualitative understanding of the spectrum of 7Be. Low-lying states form an Elliott SU(3) spectrum, while an Sp(3,R) excitation gives rise to an excited rotational band with strong quadrupole connections to the ground state band.

    Comments:
    7 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2008.05522 [pdf]
    PRL(2020)·37 citations
  2. 02

    [Submitted on 4 Aug 2020]

    Catalysis of Transmutations by Heavy Electron Quasiparticles in Crystallites

    Anthony Zuppero · Thomas J. Dolan

    This article describes our hypothesis on how transmutations may be induced by solid state effects in a crystalline lattice. We discuss the chemical reaction case, our extension to the nuclear binding case, and a tri-body model of a heavy electron quasiparticle catalyzing the binding of two nearby ions. For a given primary reaction we can estimate the required electron mass threshold m*, identify possible reaction products, estimate tunneling probabilities, and calculate energies available for each path. We compare model predictions with experimental data of transmutations, and consider hazards associated with experiments.

    Comments:
    28 pages, 19 figures
    Subjects:
    Nuclear Theory (nucl-th); cond-mat.mtrl-sci (cond-mat.mtrl-sci)
    arXiv:
    2008.05603 [pdf]
    0 citations
  3. 03

    [Submitted on 13 Aug 2020]

    Simulating core excitation in breakup reactions of halo nuclei using an effective three-body force

    P. Capel · D. R. Phillips · H.-W. Hammer

    We extend our previous calculation of the breakup of 11Be using Halo Effective Field Theory and the Dynamical Eikonal Approximation to include an effective 10Be-n-target force. The force is constructed to account for the virtual excitation of 10Be to its low-lying 2+ excited state. In the case of breakup on a 12C target this improves the description of the neutron-energy and angular spectra, especially in the vicinity of the 11Be 5/2+ state. By fine-tuning the range parameters of the three-body force, a reasonable description of data in the region of the 3/2+ 11Be state can also be obtained. This sensitivity to the three-body force's range results from the structure of the overlap integral that governs the 11Be s-to-d-state transitions induced by the three-body force.

    Comments:
    Accepted for publication within Physics Letters B; 9 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2008.05898 [pdf]
    PLB(2022)·12 citations
  4. 04

    [Submitted on 13 Aug 2020]

    Microscopic derivation of density functional theory for superfluid systems based on effective action formalism

    Takeru Yokota🇯🇵 · Haruki Kasuya🇯🇵 · Kenichi Yoshida🇯🇵 · Teiji Kunihiro🇯🇵

    Density-functional theory for superfluid systems is developed in the framework of the functional renormalization group based on the effective action formalism. We introduce the effective action for the particle-number and nonlocal pairing densities and demonstrate that the Hohenberg-Kohn theorem for superfluid systems is established in terms of the effective action. The flow equation for the effective action is then derived, where the flow parameter runs from to , corresponding to the non-interacting and interacting systems. From the flow equation and the variational equation that the equilibrium density satisfies, we obtain the exact expression for the Kohn-Sham potential generalized to including the pairing potentials. The resultant Kohn-Sham potential has a nice feature that it expresses the microscopic formulae of the external, Hartree, pairing, and exchange-correlation terms, separately. It is shown that our Kohn-Sham potential gives the ground-state energy of the Hartree-Fock-Bogoliubov theory by neglecting the correlations. An advantage of our exact formalism lies in the fact that it provides ways to systematically improve the correlation part.

    Comments:
    26 pages, 1 figure, v2: sentences added to abstract & introduction, symbols unified
    Subjects:
    Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con); High Energy Physics — Theory (hep-th)
    arXiv:
    2008.05919 [pdf]
    PTEP(2021)·11 citations
  5. 05

    [Submitted on 13 Aug 2020] (cross-list from hep-ph)

    Sum rule for the Compton amplitude and implications for the proton-neutron mass difference

    J. Gasser (U. Bern, AEC)🇨🇭 · H. Leutwyler (U. Bern, AEC)🇨🇭 · A. Rusetsky (U. Bonn, BCTP)🇩🇪

    The Cottingham formula expresses the leading contribution of the electromagnetic interaction to the proton-neutron mass difference as an integral over the forward Compton amplitude. Since quarks and gluons reggeize, the dispersive representation of this amplitude requires a subtraction. We assume that the asymptotic behaviour is dominated by Reggeon exchange. This leads to a sum rule that expresses the subtraction function in terms of measurable quantities. The evaluation of this sum rule leads to .

    Comments:
    26 pages, 9 figures. Update, matches the version published in EPJC
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2008.05806 [pdf]
    EPJC(2020)·28 citations
  6. 06

    [Submitted on 13 Aug 2020] (cross-list from hep-ph)

    Particle Production in AgAg Collisions at GeV within a Hadronic Transport Approach

    Jan Staudenmaier🇩🇪 · Natey Kübler🇩🇪 · Hannah Elfner🇩🇪

    Heavy-ion collisions at low beam energies explore the high density regime of strongly-interacting matter. The dynamical evolution of these collisions can be successfully described by hadronic transport approaches. In March 2019, the HADES collaboration has taken data for AgAg collisions at GeV and in this work, we provide predictions for particle production and spectra within the Simulating Many Accelerated Strongly-interacting Hadrons (SMASH) approach. The multiplicities and spectra of strange and non-strange particles follow the expected trends as a function of system size. In particular, in AuAu collisions, much higher yields of double-strange baryons were observed experimentally than expected from a thermal model. Therefore, we incorporate a previously suggested mechanism to produce baryons via rare decays of high mass resonances and predict the multiplicities. In addition, we predict the invariant mass spectrum for dilepton emission and explore the most important sources of dileptons above 1 GeV, that are expected to indicate the temperature of the medium. Interestingly, the overall dilepton emission is very similar to the one in AuAu collisions at GeV, a hint that the smaller system at a higher energy behaves very similar to the larger system at lower beam energy.

    Comments:
    13 pages, 13 figures, text files with the data to reproduce the figures provided in source; replaced with published version, only minor changes and 1 figure removed
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2008.05813 [pdf]
    PRC(2021)·12 citations
  7. 07

    [Submitted on 13 Aug 2020] (cross-list from hep-ph)

    Renormalization Group Studies of Dense Relativistic Systems

    Jens Braun🇩🇪 · Timon Dörnfeld🇩🇪 · Benedikt Schallmo🇩🇪 · Sebastian Töpfel🇩🇪

    Dense relativistic matter has attracted a lot of attention over many decades now, with a focus on an understanding of the phase structure and thermodynamics of dense strong-interaction matter. The analysis of dense strong-interaction matter is complicated by the fact that the system is expected to undergo a transition from a regime governed by spontaneous chiral symmetry breaking at low densities to a regime governed by the presence of a Cooper instability at intermediate and high densities. Renormalization group (RG) approaches have played and still play a prominent role in studies of dense matter in general. In the present work, we study RG flows of dense relativistic systems in the presence of a Cooper instability and analyze the role of the Silver-Blaze property. In particular, we critically assess how to apply the derivative expansion to study dense-matter systems in a systematic fashion. This also involves a detailed discussion of regularization schemes. Guided by these formal developments, we introduce a new class of regulator functions for functional RG studies which is suitable to deal with the presence of a Cooper instability in relativistic theories. We close by demonstrating its application with the aid of a simple quark-diquark model.

    Comments:
    19 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2008.05978 [pdf]
    PRD(2021)·37 citations

Affiliations

first authorsco-authorsvia INSPIRE